Surface Flinger: return false from ColorLayer::onPreComposition()

When setting a color on ISurfaceComposerClient::eFXSurfaceColor,
eTransactionNeeded will be set and SurfaceFlinfer will
process it as part of the transaction. There is no need for
a second invalidate for eFXSurfaceColor as there is no
buffer associated with it.

Bug: 112345149
Bug: 113091768
Test: adb shell /data/nativetest64/SurfaceFlinger_test/SurfaceFlinger_test
Change-Id: I6c70492f2de317ce839d516e910d95091cb4b351